Terminal structure for coil forms



July 10, 1951 A. NOYES, JR

TERMINAL STRUCTURE FOR COIL FORMS Filed June 30, 1948 g wk M M lPatented July 10, 1951 TERMINAL STRUCTURE FOR COIL FORMS Atherton Noyes,J12, Mountain Lakes, N. J., as-

signor to Aircraft Radio Corporation, Boonton, N. J a corporation of NewJersey Application June 30, 1948, Serial No. 36,081

Claims.

This invention relates in general to electrical coils and in particularto an improved construction for a combined coil form and lead-offassembly for the terminal ends of the coil.

In the past, considerable difficulty has been experienced in providing asatisfactory anchor and lead-off for the terminal ends of the coil, andthe problem has been especially difficult where the form and coils areof small diameter i. e. of the order of one-fourth of an inch or lessand a multiplicity of leads are taken out at the same end of the form.Ceramic coil forms have the advantage of permanence of dimensions withage and under conditions of high humidity, temperature variations andthe like, and they can readily be ground to very close diametraltolerances, but the characteristics of the material are such that theattachment of coil terminals in a satisfactory manner to the end or endsof ceramic coil forms has long been a problem.

Primary objects of this invention are to provide improved lead-offarrangements for formmounted coils which have relatively few anddifferent parts, are easily and quickly assembled, and which assure arigid, fixed position of the lead-off conductors which makes accidentalshort-circuiting of the coil leads virtually impossible. Objects are toprovide a coil form and lead-elf assembly including two insulatedterminals in each end of small diameter coil forms 7 without materiallyincreasing the effective diameter of the assembly, whereby a closemounting of a number of such assemblies in a compact array is madepossible. Further objects are to provide coil terminals or lead-offassemblies of the type stated which may readily be mounted on the endsof ceramic rod coil forms.

Other objects and advantages of the improved construction will becomemore apparent from the following detailed description of a preferredembodiment of the invention and the accompanying drawings in which:

Fig. 1 is a side elevation showing an assembly of form-mounted coilunits, each of which is constructed in accordance with the principles ofthe invention; Fig. 2 is an end view of the same; Fig. 3 is afragmentary view in perspective of one of the coil forms showing thelead-oil conductor assembly at one end of the form; Fig. 4 is anexploded View showing the various com ponents of the assemblyillustrated in Fig. 3; Fig, 5 is a fragmentary view of one of the coilforms, partly in section and partly in elevation with the lead-citconductors assembled; Fig. 6 is an end view at an intermediate stage inthe assembly showing the inner, grooved clamping disc with the lead-offconductors in place; Fig. 7 is an end view of one of the clamping discswith the lead-off conductors removed; Figs. 8 and 9 are diametralsectional views taken on lines 8-8 and 99, respectively of Fig. '1; andFigs. 10 and 11 are fragmentary perspective views of rod coil formshaving different constructions for anchoring the lead-off wires againstdisplacement.

Referring now to the drawings, and in particular to Figs. 1 and 2, Ihave there illustrated a twelve unit group of form-mounted coils, therebeing four rows of wire wound forms in one direction and three rows inthe other direction. The coil forms, designated by reference numeral l,are held in spaced relation between mounting plates 2, 3 which in turnare received in grooves 4 in parallel spaced plates 5, 6 secured toopposite walls of a box I.

In the illustrated embodiment, each of the forms I has two coils 8, 9 ofinsulated wire wound together upon it and the opposite ends of each coil8a, 8b and 9a, 9?) lie at opposite ends of the form. All twenty-fourcoils are electrically connected in series resulting in two leads Ill,II by which the coil group can then be connected into the circuit forwhich it is intended.

As previously explained, the primary object of the present invention isto provide an improved lead-off arrangement for the ends Ba-8b and 9a%of the coils at the ends of the cylindrical forms I, the Figs. 3-9clearly illustrate the principal structural features upon whichpatentable novelty is predicated. As shown in these views. each end ofthe forms I is recessed and tapped at l 2 to receive a screw I3 having aslotted cylindrical head I3 1 by which two lead-olT conductors l6, I!are secured tightly in place between a pair of insulating discs I4, I5and upon the end of the form I. The two leads I6, I! which are identicalare preferably made from comparatively stifl round wire and includeintermediate, arcuate laterally offset portions Ilia, Ila. The latterwhich lie in a plane perpendicular to the end por tions I51), I andI71), I10 and extend through substantially of arc are seated in ashallow circular groove Ida in one face of a circular inner clampingdisc I4, i. e. the disc next to the end face la of the form, and theinner ends lib, I'I'b of the two lead-01f conductors pass throughaxially extending apertures Mb in the disc I4, it being noted that thesetwo apertures are located apart and are in radial alignment with thegroove M11 in relation to the disc axis. Flats Ic, Id spaced 180 apartare provided tween the mounting plates 2, 3.

3 at each end of the form I, and when assembled, the inner ends I6b, [lbof the lead-off conductors lie flat against them so as to prevent anyaccidental turning of the lead-off conductors about the axis of theform.

The outer disc I is structurally identical with the inner disc I4 andthe circular groove and apertures therein through which the outer endsI60, I of the lead-off conductors are passed are identified by numeralsI5a, I511. The depth of the grooves Ila, I5a is made somewhat less thanone half the diameter of the lead oif conductors I6, I! so as to providea good clamping action on the latter.

The manner of assembly is obvious from the exploded view in Fig. 4 inwhich all component parts have been oriented with respect to the axis ofthe form to the exact positions they occupy upon assembly. Referring toFig. 4 it will be observed that the grooved surfaces of the discs I4,I5, confront each other and that their respective apertures Mb, I51) aredisplaced 90 with respect to the form axis. Hence when the componentsare assembled and screw I3 which passes through axial openings I40, I50in the discs is screwed into the end face Ia, the intermediate arcuateoffset portions Ifia, I'Ia of the two lead-ofi conductors will beclamped tightly between the discs I4, I5 in the co-registering grooves Ila, I511; the inner ends I61), I11) of the conductors will lie againstthe form flats Ic, Id which look the parts against rotation; and theouter ends Ific, Ilc of the lead-off conductors will extend parallel tothe form axis and 180 apart so as to provide a maximum spacing betweenthe conductors.

As shown in Figs. 1 and 2, the inner ends Ifib, I'Ib of the lead-offconductors are then soldered to the coil ends 8a, 8b and 9a, 9b, and theouter ends I60, We of the adjacent coils interconnected by soldering atboth ends of the twelve unit assembly to provide the desired series coilconnection.

Finally it will also be observed from Figs. 1 and 2 that nothingadditional in the way of structure is necessary for support of the coilforms I be- The latter are provided with as many apertures 2a, 3a asthere are forms to be supported, these apertures being so sized as tomake a snug lit with the cylindrical heads I3a of the screws, and a pairof small openings are provided closely adjacent to each aperture 2a, 3ato pass the lead-off conductor ends I60, I10. It is often desirable, asshown in Fig. 1, to make the thickness of the mounting plates 2, 3slightly in excess of that of the screw heads so that when assembled,the screw heads lie below the outer faces of the plates thereby tofacilitate interconnections between the several coils and also to reducethe possibility of a short circuit between leads.

The coil forms I are preferably of ceramic material when dimensional andmechanical stability are important and, whether of ceramic or of otherinsulating material, means other than the flats I'c, Id may be employedfor preventing inadvertent angular displacement of the lead-off wires,for example short and shallow grooves I extending longitudinally in adiametrical plane at the ends of the coil forms I as illustrated in Fig.M), or a short diametrically disposed slot or saw kerf I" as illustratedin Fig. 11.

In conclusion, I wish it to be understood that the specific structuralembodiment of the leadofi arrangement for small sized form-supportedwindings which has been illustrated and described is but typical of theinvention and that various modifications thereof may be preferred byothers in this art but without, however, departing from the spirit andscope of the invention as expressed in the appended claims.

I claim:

1. A combined coil support and lead-off assembly comprising an elongatedform adapted to receive the coil, a lead-off conductor having a lateraloffset portion intermediate the terminal ends thereof, a pair ofconfronting discs at one end of said form each of which is provided withan aperture extending between the opposite faces thereof, said offsetportion of said conductor being seated between the confronting faces ofsaid discs with the terminal ends of said conductor extending throughthe disc apertures aligned therewith, and means securing said discstogether and to the end of the said form thereby to clamp the oifsetportion of said conductor between said discs.

2. A combined coil support and lead-01f assembly as defined in claim 1wherein the end of said form is provided with a flat against which reststhe inner terminal end of said lead-off conductor.

3. A combined coil support and lead-off assembly as defined in claim 1wherein the end of the coil form is provided with a shallowlongitudinally extending groove in which the inner end of the lead-offconductor is seated.

4. A combined coil support and lead-off assembly comprisng an elongatedform adapted to receive the coil, a lead-off conductor having a lateraloffset portion intermediate the terminal ends thereof, a pair ofconfronting discs at one end of said form each of which is provided withan aperture extending between the opposite faces thereof, said offsetportion of said conductor being seated in co-registering groovesprovided in the confronting faces of said discs with the terminal endsof said conductor extending through the disc apertures alignedtherewith, and means se curing said discs together and to the end ofsaid form thereby to clamp the offset portion of said conductor betweensaid discs.

5. A combined coil support and lead oif assembly comprising an elongatedform adapted to receive the coil, a pair of lead-ofi conductors each ofwhich is provided with a lateral offset portion intermediate theterminal ends thereof, a pair of confronting discs at one end of saidform each of which is provided with a pair of spaced apertures extendingbetween the opposite faces thereof, said offset portions of saidconductors being seated in spaced relation between the confronting facesof said discs with the terminal ends thereof extending through anaperture in each disc aligned therewith, and means securing said discstogether and to the end of said form thereby to clamp the offsetportions of said conductors between said discs.

6. A combined coil support and lead-01f assembly as recited in claim 6wherein the end of the coil form is provided with a diametricallydisposed slot, the terminal ends of the lead-01f conductors beingarranged in opposite sides of said slot.

7. A combined support and lead-off assembly for a coil comprising anelongated form adapted to receive the coil, a pair of lead-offconductors: each of which includes an intermediate portion laterallyoffset from the terminal ends thereof, a. pair of confronting discsarranged at one end of said form, said discs having co-registeringgroovesin their confronting faces and each including a pair of aperturesspaced apart extending from the groove to the opposit face, said discsbeing disposed with the respective apertures therein in offset relationcorresponding to the offset portions of said conductors, and saidterminal ends of said conductors extending through said apertures withthe offset portions thereof seated in said grooves, and means securingsaid discs together and to the end of said form thereby to clamp theconductor offset portions between said discs.

8. A combined coil support and lead-off assembly comprising an elongatedform adapted to receive the coil, a pair of lead-oh: conductors each ofwhich includes an intermediate arcuate portion extending through 90laterally offset from the terminal ends thereof, a pair of confrontingdiscs at one end of said form, said discs having co-registering circulargrooves in their confronting faces and each including a pair ofapertures spaced 180 apart extending from said groove to the oppositeface, said discs being disposed with the respective pairs of aperturesat right angles, and said terminal ends of said conductors extendingthrough said apertures with the offset portions thereof seated in saidgrooves, and means securing said discs together and to the end of saidform to thereby clamp the offset portions of said conductors betweensaid discs.

9. A combined coil support and lead-off assembly comprisin an elongatedform adapted to receive a pair of coils the ends of each of whichterminate at opposite ends of said form, and a lead-off assembly at eachend of said support for the coil ends, each said assembly comprising apair of lead-off conductors each of which includes an intermediateportion offset laterally from the terminal ends thereof, a pair ofconfronting discs each of which is provided with an aperture extendinbetween the opposite faces thereof, the offset portions of saidconductors being seated in spaced relation between the confronting facesof said discs with the terminal ends of said conductors extendingthrough the apertures in said discs aligned therewith, and meanssecuring said discs together and to the end of said form thereby toclamp the offset portions of said conductors between said discs.

10. A combined coil support and lead-off assembly comprising a coilform, a pair of confronting insulating discs each having a centralaperture and a second off-center aperture extending between the oppositefaces thereof, a lead-off conductor having an intermediate lateraloffset portion seated between the confronting faces of said discs withthe end portions passing through the off-center apertures, and aclamping screw extending through the central apertures in said discs andthreaded into the end face of said form for securing the offset portionof said leadoff conductor between said discs and also securing thelatter to said form, the end of said form including means cooperativewith said conductor for holding the latter and said discs inpredetermined angular relation to said form.

ATHERTON NOYES, J R.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 737,720 Duncan Sept. 1, 1903936,669 Rypinski Oct. 12, 1909 1,715,018 Von Brockdorff May 28, 19292,233,905 Wilson Mar. 4, 1941 FOREIGN PATENTS Number Country Date242,718 Switzerland Oct. 16, 1946 328,588 Germany June 13, 1919 436,383Great Britain Oct. 10, 1935 463,348 Great Britain Mar. 30, 1937Certificate of Correction Patent No. 2,559,988 July 10, 1951 ATHERTONNOYES, JR.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows:

Column 4, line 30, for comprisng read comprising; line 61, for the claimreference numeral 6 read 5 and that the said Letters Patent should beread as corrected above, so that the same may conform to the record ofthe case in the Patent Ofiice. Signed and sealed this 18th day ofSeptember, A. D. 1951.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.

Certificate of Correction Patent No. 2,559,988 July 10, 1951 ATHERTONNO-YES, JR.

It is hereby certified that error appears in the printed specificationof the above numbered patent requiring correction as follows:

Column 4, line 30, for comprisng read compacting; line 61, for the claimreference numeral 6 read 5;

and that the said Letters Patent should be read as corrected above, sothat the same may conform to the record of the case in the PatentOflice. Signed and sealed this 18th day of September, A. D. 1951.

THOMAS F. MURPHY,

Assistant Gammissz'oner of Patents.

